Friday, January 05, 2007

Bush Approval: CBS at 30%, Trend at 33.5%

The first poll of the new year, by CBS News, taken 1/1-3/07 finds approval of President Bush at 30%, with 63% disapproval. This is the lowest approval reading in any CBS News poll for this administration. The result also pulls the trend estimate down to 33.5, also a low for the administration. However, it is important to discount the trend estimate until more data are available. This is the first new poll in over two weeks and the very low CBS result standing by itself at the end of the time series is exerting an unusually strong influence on the trend estimate. Until more data for 2007 come in the trend estimate should be viewed with some skepticism. Prior to the addition of the CBS result, the trend estimate stood at 34.4%, an estimate supported by a substantial number of polls taken through 12/21/06. A reasonable guess is that the current standing is between 33.5 and 34.4, which is still near the low point for the administration, but not necessarily the very lowest well supported estimate.

At about 4 points below trend, the CBS News poll is short of being a statistical outlier, especially once the typical CBS "house effect" of -2.06 is considered. This means that CBS/NYT polls are on average about 2 points lower in approval than the mean across all polls. Thus there is not clear evidence that the CBS poll should be discounted entirely, but the best bet would still be that approval is closer to 34% than it is to 30%.

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About Me

I am co-founder of Pollster.com and founder of PollsAndVotes.com.
I am also a professor of political science at the University of Wisconsin, where I teach statistical analysis of polls, public opinion and election results. Data visualization is central to my approach to analysis.
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